1. Field of the Invention
The present invention relates to a semiconductor memory device and a method of driving the same, and more particularly to, a semiconductor memory device and a method of driving the same which can improve repair efficiency by dividing a memory cell array into a plurality of blocks and segments, and repairing only a segment in which a defective cell is occurred to a redundancy segment.
2. Discussion of Related Art
A semiconductor memory device generally has a row and a column. That is, as having a plurality of memory cells arranged into a matrix form, the semiconductor memory device becomes an ultra-high integrated semiconductor memory device which has much more memory cells by increasing of a memory capacity. On the other hand, the semiconductor memory device gets defective memory cells by various reasons such as its own defect of a semiconductor substrate, a defect of design layout, a defect generated during processing, and so on. Accordingly, for improving a yield to use the semiconductor memory device even though there is a defective memory cell occurred therein, there is a method introduced that the defective memory cell is repaired with a redundancy cell by comprising the redundancy cell in a row and a column in a memory cell array.
A repairing method of a defective memory cell in the conventional art repairs a row block with a defective cell to a redundancy row block, regardless of the number of defective cells. That is, this repairing method repairs the row block with the defective memory cell to the redundancy row block even when one bit defect is occurred in a specific row block. Accordingly, when one bit defect is generated in the redundancy cell, the conventional repairing method can not use the whole of the one redundancy row block.